package server

import (
	"fmt"
	"net/http"
	"slices"
	"strings"
	"time"

	"github.com/StevanFreeborn/chirpy/internal/api"
	"github.com/StevanFreeborn/chirpy/internal/auth"
	"github.com/StevanFreeborn/chirpy/internal/database"
	"github.com/google/uuid"
)

const (
	ascending  = "asc"
	descending = "desc"
)

type createChirpRequest struct {
	Body   string `json:"body"`
	UserId string `json:"user_id"`
}

type chirpResponse struct {
	Id        string `json:"id"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
	Body      string `json:"body"`
	UserId    string `json:"user_id"`
}

// toChirpResponse maps a database Chirp to its API response shape.
func toChirpResponse(c database.Chirp) chirpResponse {
	return chirpResponse{
		Id:        c.ID.String(),
		CreatedAt: c.CreatedAt.Format(time.RFC3339),
		UpdatedAt: c.UpdatedAt.Format(time.RFC3339),
		Body:      c.Body,
		UserId:    c.UserID.String(),
	}
}

// HandleCreateChirp creates a chirp for the authenticated user.
func (s *Server) HandleCreateChirp(w http.ResponseWriter, r *http.Request) {
	bearerToken, err := auth.GetBearerToken(r.Header)

	if err != nil {
		api.WriteError(w, http.StatusUnauthorized, "You are not authorized to perform this action")
		return
	}

	requestUserId, err := auth.ValidateJWT(bearerToken, s.jwtSecret)

	if err != nil {
		api.WriteError(w, http.StatusUnauthorized, "You are not authorized to perform this action")
		return
	}

	createChirpRequest, err := api.DecodeJSON[createChirpRequest](r)

	if err != nil {
		api.WriteError(w, http.StatusBadRequest, err.Error())
		return
	}

	if len(createChirpRequest.Body) > 140 {
		api.WriteError(w, http.StatusBadRequest, "Chirp is too long")
		return
	}

	createChirpParams := database.CreateChirpParams{
		Body:   cleanProfanity(createChirpRequest.Body),
		UserID: requestUserId,
	}

	createdChirp, err := s.db.CreateChirp(r.Context(), createChirpParams)

	if err != nil {
		api.WriteError(w, http.StatusInternalServerError, "Failed to create chirp. 🤷🏻‍♂️")
		return
	}

	api.WriteJSON(w, http.StatusCreated, toChirpResponse(createdChirp))
}

// HandleGetChirps lists chirps, optionally filtered by author_id and sorted by
// the sort query parameter.
func (s *Server) HandleGetChirps(w http.ResponseWriter, r *http.Request) {
	authorId := r.URL.Query().Get("author_id")
	sortDir := r.URL.Query().Get("sort")

	hasAuthorId := strings.TrimSpace(authorId) != ""
	hasSort := strings.TrimSpace(sortDir) != ""

	validAuthorId, err := uuid.Parse(authorId)

	if hasAuthorId && err != nil {
		api.WriteError(w, http.StatusBadRequest, "Author id must be a valid uuid")
		return
	}

	if hasSort && sortDir != ascending && sortDir != descending {
		api.WriteError(w, http.StatusBadRequest, fmt.Sprintf("Sort direction must be either '%s' or '%s'", ascending, descending))
		return
	}

	if !hasSort {
		sortDir = ascending
	}

	var existingChirps []database.Chirp

	if hasAuthorId {
		existingChirps, err = s.db.GetChirpsByAuthor(r.Context(), validAuthorId)
	} else {
		existingChirps, err = s.db.GetAllChirps(r.Context())
	}

	if err != nil {
		api.WriteError(w, http.StatusInternalServerError, "Unable to retrieve chirps")
		return
	}

	slices.SortFunc(existingChirps, func(a, b database.Chirp) int {
		if sortDir == descending {
			return b.CreatedAt.Compare(a.CreatedAt)
		}

		return a.CreatedAt.Compare(b.CreatedAt)
	})

	chirps := make([]chirpResponse, 0, len(existingChirps))

	for _, c := range existingChirps {
		chirps = append(chirps, toChirpResponse(c))
	}

	api.WriteJSON(w, http.StatusOK, chirps)
}

// HandleGetChirp returns a single chirp by id.
func (s *Server) HandleGetChirp(w http.ResponseWriter, r *http.Request) {
	chirpId := r.PathValue("id")
	validChirpId, err := uuid.Parse(chirpId)

	if err != nil {
		api.WriteError(w, http.StatusBadRequest, "Chirp id is not valid. id must be valid UUID.")
		return
	}

	existingChirp, err := s.db.GetChirpById(r.Context(), validChirpId)

	if err != nil {
		api.WriteError(w, http.StatusNotFound, "No chirp with given id found.")
		return
	}

	api.WriteJSON(w, http.StatusOK, toChirpResponse(existingChirp))
}

// HandleDeleteChirp deletes a chirp owned by the authenticated user.
func (s *Server) HandleDeleteChirp(w http.ResponseWriter, r *http.Request) {
	accessToken, err := auth.GetBearerToken(r.Header)

	if err != nil {
		api.WriteError(w, http.StatusUnauthorized, "You are not authorized to perform this action")
		return
	}

	requestUserId, err := auth.ValidateJWT(accessToken, s.jwtSecret)

	if err != nil {
		api.WriteError(w, http.StatusUnauthorized, "You are not authorized to perform this action")
		return
	}

	chirpId := r.PathValue("id")
	validChirpId, err := uuid.Parse(chirpId)

	if err != nil {
		api.WriteError(w, http.StatusBadRequest, "Chirp id must be a valid uuid for an existing chirp")
		return
	}

	existingChirp, err := s.db.GetChirpById(r.Context(), validChirpId)

	if err != nil {
		api.WriteError(w, http.StatusNotFound, "Chirp id must be a valid uuid for an existing chirp")
		return
	}

	if existingChirp.UserID != requestUserId {
		api.WriteError(w, http.StatusForbidden, "You can not delete a chirp that does not belong to you")
		return
	}

	if err := s.db.DeleteChirpById(r.Context(), existingChirp.ID); err != nil {
		api.WriteError(w, http.StatusInternalServerError, "Unable to delete chirp")
		return
	}

	api.WriteJSON(w, http.StatusNoContent, nil)
}